1. Field Of The Invention
The present invention relates, in general, to the field of unmanned aerial vehicle (UAVs). More specifically, it is directed to the field of UAVs capable of vertical take-offs and landings (VTOLs) with one or more ducted fans as the propulsion system.
2. Description of the Related Art
An unmanned aerial vehicle (UAV) is an unpiloted and/or remotely controlled aircraft. UAVs can be either remotely controlled or flown autonomously based on pre-programmed flight plans or more complex dynamic automation and vision systems. UAVs are currently used in a number of military roles, including reconnaissance and attack scenarios. An armed UAV is known as an unmanned combat air vehicle (UCAV).
UAVs are also used in a limited number of civil applications such as firefighting when a human observer would be at risk, police observation of civil disturbances and crime scenes, and reconnaissance support in natural disasters. UAVs are often preferred for missions that are too dull, dirty, dangerous, or expensive for manned aircraft.
There are a wide variety of UAV shapes, sizes, configurations, and characteristics. Modern UAVs are capable of controlled, sustained, level flight and are powered by one or more jets, reciprocating engines, or ducted fans.
Payloads carried by UAVs in civil applications normally include an optical sensor (which may capture image or video in the visible or infrared spectrums, for example) and/or a radar system. A UAV's sophisticated sensors can provide photographic-like images through clouds, rain or fog, and in daytime or nighttime conditions; all in real-time. A concept of coherent change detection in synthetic aperture radar images, for example, allows for search and rescue abilities by determining how terrain has changed over time.
Providing a vertical takeoff and landing (VTOL) capability allows improved portability and allows a UAV to maneuver into situations and be utilized in areas that a fixed-wing aircraft may not.
While UAV's have been utilized extensively in military roles, their use in civil applications has been limited due to cost concerns, export regulations (such as International Traffic in Arms Regulations—ITAR), civil airspace regulations, and safety regulations, for example. Additionally, various regulations related to autonomous flying objects having a weight that could pose a hazard to life and/or property may have limited further penetration of UAV's into civil applications.